With the ever growing use of containers in silvaculture, agriculture and horticulture for the growth of plants from either seed or cuttings to stages suitable for transplanting, many systems and arrangements are known in the prior art which in one way or another purport to provide efficient, economical procedures and devices for plant growing containers. Some systems contemplate containers that are nested or knocked-down for economical packed shipment of the containers from manufacturers to nurseries and greenhouses. Other systems contemplate trays and blocks having plant growing cavities for efficient growing of a large number of plants in a greenhouse operation. Other systems are known that use devices which are supposed to make the transplanting or outplanting operation efficient and labor saving. Thus, while one system or another in the prior art provides one or more labor saving devices in the total procedure from manufacture to transplanting site, no known system includes as many unique labor saving procedures and devices as the system of the subject invention.